We propose to use recombinant DNA techniques to isolate DNA sequences located on human chromosome 11. These DNA sequences will be localized to specific regions of the chromosome by a deletion mapping procedure in which cloned DNA segments will be hybridized to DNA isolated from hybrid cell lines carrying deletions of various lengths of the short arm of chromosome 11. The DNA sequences isolated by this procedure will be used in a number of studies in which the genetics of chromosome 11 play an important role. These include: 1. Mapping of deletions of 11p which are associated with aniridia and Wilms tumor. 2. Identification of sites in the DNA of chromosome 11 which exhibit polymorphism with respect to sensitivity to restriction endonuclease digestion. These sites will then be used as markers in two types of studies: a. Diagnosis of thalassemia and hemoglobinopathies by analysis of linked markers. b. Determination of the possible linkage of familial aniridia to the 11p13 chromosomal segment. 3. A long-range objective of this proposal will be to use the DNA probes isolated in this study to analyze in detail the structure and function of specific regions of chromosome 11.